trunnion ball valve leakage rate question

[Indy]

Hi,
I have a question with regards to leakage rate and tight shutoff. A supplier has specified for tight shutoff of the valve and the valve vendor has offered a valve conforming to leakage rate B. from research this rate is 0.3 DN. Is there a reference in a standard that says this leakage rate will conform to a tight shutoff?


thanks

 

[mk3223]

May refer to API-598 for the leakage rate for the different valve types of typical piping valves. Basically, it's depended on the type of valve with the seat material.
The resilient seated valves can be the choice if the true zero leakage is required.

 

[Indy]

Thanks for the reply. The supplier has said max allowable leakage rate is sm3/hr so using the leakage formula above on an 8” line the valve leakage rate is within this limit. I am unsure Why would they ask for tight shut off is this rate is allowable?

Thanks

 

[GD2]

Leakage Rate A, B, C, D etc are ISO API 6D/ISO 2508 designation in cu.mm/sec and drops/sec,or bubbles/sec. API 598 give leakage rates in terms of drops/min or bubbles/min.

Both standards rates are dependent on size.

API 6D valves are typically used in pipelines whereas other ASME/API valves are used in other applications like process/chemical plants.

GDD
Canada